refactor: update remnawave API types for v2.7.0

- ServerInfo: remove cpu_physical_cores, memory_available
- NodeInfo: replace cpu_count/cpu_model/total_ram with versions/system,
  xray_uptime changed to number, users_online now required
- NodeStatus: same field updates, remove dead uptime field
- Extract formatUptime to shared utils/format.ts
- Update AdminRemnawave and AdminDashboard components

src/api/admin.ts

@@ -162,15 +162,11 @@ export interface NodeStatus {
   is_disabled: boolean;
   users_online: number;
   traffic_used_bytes?: number;
-  uptime?: string;
-  xray_version?: string;
-  node_version?: string;
   last_status_message?: string;
-  xray_uptime?: string;
+  xray_uptime: number;
   is_xray_running?: boolean;
-  cpu_count?: number;
-  cpu_model?: string;
-  total_ram?: string;
+  versions?: { xray: string; node: string } | null;
+  system?: Record<string, unknown> | null;
   country_code?: string;
 }